1. Field of the Invention
The present invention relates generally to a surgical electrode lead and more specifically relates to a heart wire for temporary application.
2. Description of the Prior Art
The use of temporary leads for pacing and monitoring purposes is quite common. Specially designed leads are used for such temporary applications which are much lighter and less durable than permanent leads since extended flex life is not required. It is still critical, however, that electrodes be properly affixed to tissue to permit the required transfer of electrical energy. This electrical contact must be established in a manner which permits convenient and safe removal of the lead with minimal permanent scarring and other effects. Furthermore, for epicardial applications, most permanent leads are more costly than is felt justified for temporary use.
Ackerman teaches construction of temporary leads for curing caridac arrest in U.S. Pat. Nos. 3,485,247 and 3,516,412. The former reference uses a hookshaped tip for affixing the lead whereas the latter uses resiliencey of shape. Neither of these techniques is suitable for most applications, however, as both leads are intended to be percutaneously inserted and actually puncture the myocardium. Because of the permanent effects of this technique, it is not useful under routine circumstances.
The primary method of affixing temporary epicardial leads is with sutures. Typically, this technique provides the greatest reliability with minimal permanent damage. Sutures were used in the earliest pacing applications for affixing all leads. U.S. Pat. No. 3,244,174, issued to Wessey, et al, teaches a lead whose electrodes are affixed using a suture pad.
U.S. Pat. No. 3,474,791, issued to Benton, teaches a lead having insulation removed at points which permit electrical contact. The lead may have a curved surgical needle attached directly to the distal end of the conductor for inserting the lead directly into the myocardium. Additional sutures are used to further attach the lead to the epicardium. U.S. Pat. No. 3,035,583, issued to Hirsch, et al teaches the use of sutures which are conductive.
These earlier suturing techniques for affixing the electrode to the myocardium lend themselves primarily to permanent implantation, since removal of the lead is difficult. For temporary applications, the lead must be easily removable and cause minimal permanent damage. Ideally, no portion of the lead should remain in the body after use.